Skip Navigation



ToxSci Advance Access published online on August 13, 2004
Toxicological Sciences, doi:10.1093/toxsci/kfh247
Toxicological Sciences © Society of Toxicology 2004; all rights reserved
This Article
Right arrow Advance Access manuscript (PDF) Freely available
Right arrow All Versions of this Article:
82/1/106    most recent
kfh247v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Right arrow Disclaimer
Google Scholar
Right arrow Articles by Anne McNabb, F. M.
Right arrow Articles by Larsen, C. T.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Anne McNabb, F. M.
Right arrow Articles by Larsen, C. T.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

Received May 27, 2004
Accepted August 4, 2004

Environmental Toxicology

Does Thyroid Function in Developing Birds Adapt to Sustained Ammonium Perchlorate Exposure?

F. M. Anne McNabb 1*, Darryl A. Jang 1, Calvert T. Larsen 2

1 Department of Biology, Virginia Tech, Blacksburg VA 24061-0406, USA
2 Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Virginia Tech, Blacksburg VA 24061-0443, USA

* To whom correspondence should be addressed. E-mail: happy{at}vt.edu.


  Abstract

The effects of a wide range of ammonium perchlorate (AP) concentrations, in drinking water on thyroid function in bobwhite quail chicks was investigated at 2, 4 and 8 weeks of exposure. We measured plasma thyroid hormones (THs) to evaluate organismal thyroid status, thyroid weights to evaluate hypothalamic-pituitary-thyroid (HPT) axis activation and thyroidal TH content to assess TH stores. At the highest AP exposures plasma THs were decreased, thyroid glands were hypertrophied and thyroidal TH content was decreased. As in our previous studies, thyroidal thyroxine (T4) content was the most sensitive indicator of decreased thyroid function, plasma T4 and thyroid weight were much less sensitive. The lack of sensitivity of these variables appears to result from cyclic patterns of thyroid responses involving the HPT axis and intermittent release of stored THs from the thyroid gland. With sustained AP exposure (8 weeks), at the lowest range of AP concentrations used, chicks showed adaptation in thyroid function that fully compensated for the initial (2 week) effects of AP. At the intermediate AP concentrations there was partial compensation for the initial AP effects. At the highest AP exposures used thyroid function was very low throughout the study with no indication of compensatory responses. The capability of chicks to adaptively increase some aspects of their thyroid function in response to some levels of sustained AP exposure is contrary to the common generalization that developing animals are most vulnerable to environmental contaminants.

Keywords: perchlorate; thyroid; quail chicks; exposure time.
Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?


This article has been cited by other articles:


Home page
 Toxicol SciHome page
S. Mukhi and R. Patino
Effects of Prolonged Exposure to Perchlorate on Thyroid and Reproductive Function in Zebrafish
Toxicol. Sci., April 1, 2007; 96(2): 246 - 254.
[Abstract] [Full Text] [PDF]

Home page
 Toxicol SciHome page
F. Hu, B. Sharma, S. Mukhi, R. Patino, and J. A. Carr
The Colloidal Thyroxine (T4) Ring as a Novel Biomarker of Perchlorate Exposure in the African Clawed Frog Xenopus laevis
Toxicol. Sci., October 1, 2006; 93(2): 268 - 277.
[Abstract] [Full Text] [PDF]

Home page
 Eur J EndocrinolHome page
M. Boas, U. Feldt-Rasmussen, N. E Skakkebaek, and K. M Main
Environmental chemicals and thyroid function.
Eur. J. Endocrinol., May 1, 2006; 154(5): 599 - 611.
[Abstract] [Full Text] [PDF]


Disclaimer:
Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.